Focused beam reflectance measurement to optimized desalter performance and reduce downstream fouling

ABSTRACT

Performance of equipment, such as a desalter, in a refinery is monitored in real-time and on-line to minimize fouling of downstream equipment. Using an instrument to measure particles and droplets in-process allows monitoring of the various operations to optimize performance. Such measurement can also be used during crude oil blending to detect asphaltene precipitates that can cause fouling and can be used for monitoring other fouling streams.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to processing of whole crude oils, blends andfractions in refineries and petrochemical plants. In particular, thisinvention relates to monitoring performance of components in a refinery,especially monitoring performance of a desalter. This invention alsorelates to optimizing a refinery operation to mitigate fouling.

2. Discussion of Related Art

Fouling is generally defined as the accumulation of unwanted materialson the surfaces of processing equipment. In petroleum processing,fouling is the accumulation of unwanted hydrocarbon-based deposits onheat exchanger surfaces. These deposits often include inorganicmaterials as well. It has been recognized as a nearly universal problemin design and operation of refining and petrochemical processingsystems, and affects the operation of equipment in two ways. First, thefouling layer has a low thermal conductivity. This increases theresistance to heat transfer and reduces the effectiveness of the heatexchangers. Second, as deposition occurs, the cross-sectional area isreduced, which causes an increase in pressure drop across the apparatus.

Fouling in heat exchangers associated with petroleum type streams canresult from a number of mechanisms including chemical reactions,corrosion, deposit of insoluble materials, and deposit of materials madeinsoluble by the temperature difference between the fluid and heatexchanger wall.

One source of fouling is carryover of brine and solids from a desalter,which will adversely affect downstream equipment. Typically, in arefinery, raw crude oil arrives containing water and salt. Part of thesalts contained in the crude oil, particularly magnesium chloride, arehydrolysable at temperatures above 120° C. Upon hydrolysis, thechlorides are converted into hydrochloric acid, which can migrate to theoverhead portion of the distillation column and corrode the condensers.To remove the salts, the crude oil is first treated in a desalter. Thedesalter is a large vessel full of liquid that uses an electric field toseparate the crude oil from the water droplets. As it operates best at120-150° C., it is generally placed within the preheat train. Downstreamof the desalter, the crude oil is further heated in heat exchangers, asis known.

Desalters also help to remove insoluble salts and other solids that areoften found in raw crude. Corrosion byproducts, such as iron sulfides,are often found in crude oil and may originate from crude oil pipelines,tanker holds and crude storage tankage. Larger particles will settle tosome degree during desalting, whereas finer particles may not. Thelatter are known to contribute to fouling of crude preheat exchangers.Chemical additives, such as flocculants, are often added to desalters toenhance solids removal.

The impact of desalter upsets on downstream heat exchangers is a knownproblem. The aqueous brine, which contains dissolved salts such assodium chloride, when carried-over with the desalted oil leads tofouling in the crude preheat exchangers and can contribute to overheadcorrosion in the pipestill itself. Desalter upsets, such as brinecarryover, can also pass more solids to downstream equipment.

Another source of fouling is asphaltene precipitation due to blending ofincompatible crude oils. Most refineries run blends of different crudeoils and care must be taken in blending of these crudes to avoid theunwanted precipitation of asphaltenic materials. Though guidelines areavailable to assist refinery operators to avoid this situation, itoccurs nonetheless, with subsequent heat exchanger fouling.

Once heat exchangers are fouled, they must be cleaned to remove thedeposits. Otherwise, foulant deposits reduce the heat transferefficiency, which requires higher fuel consumption in downstreamatmospheric pipestill furnaces. Cleaning typically involves removing theheat exchangers from service and hydroblasting the surfaces or otherwisecleaning the surfaces to remove the deposits. The equipment must then bebrought back on-line. The frequency of required cleaning is driven bythe amount of desalter upsets and asphaltene precipitation occurring inthe equipment.

Mitigating or possibly eliminating fouling of heat exchangers can resultin huge cost savings in reduced energy usage. Reduction in fouling alsoincreases throughput and reduces maintenance and cleaning expenses.

Currently, desalter performance is not monitored. Most particulatemonitoring methods rely on light transmittance to detect particles influid streams. However, due to the optical opacity of crude oil, thesemethods cannot be used. Other methods such as acoustic based methods arehighly influenced by temperature and viscosity variations. Thus, in arefinery setting, these methods have a low level of reliability.

There is a need for monitoring the desalter performance, including theoperation and output, especially in real-time and on-line. There is alsoa need for real-time on-line monitoring of incompatibility-inducedasphaltene precipitation during crude blending.

BRIEF SUMMARY OF THE INVENTION

Aspects of embodiments of the invention relate to optimizing operationsin a processing facility to mitigate fouling of heat exchange equipment.

Another aspect of embodiments of the invention relates to monitoringoperation of desalter equipment on-line and in real-time to obtain datathat can be used to optimize operations.

The invention is directed to a process for optimizing a refiningoperation to mitigate fouling of heat exchangers, comprising processingraw crude oil in a desalter with wash water to remove particles, solublesalts, and insoluble materials from the crude oil, measuring particlesin the processed crude oil and generating data based on themeasurements, and adjusting the processing based on the data generatedfrom the measurements. The term “particles” in this context can includeany second immiscible phase found in the crude oil such as salt brinedroplets, insoluble inorganic salts, solid corrosion byproducts, mineralmaterials such as clays and aluminosilicates and asphaltenes forexample. Ideally, one would like to measure the crude oil that is cominginto the desalter and exiting the desalter and adjusting the operationof the desalter to maximize removal of brine, solids and asphaltenes.Operating parameters such as crude inlet temperature, electrostatic gridvoltage, crude/water mixing energy, water addition rate, pH of water,rate of additives to assist flocculation could all be varied dependingupon observed performance.

The process can include counting total particles, collecting the totalparticle counts and sorting the counts based on particle size.Preferably, the method of measuring the particles includes using focusedbeam reflectance.

The invention is additionally directed to a process for monitoringaqueous breakthrough in a stream of crude oil, comprising providing astream of crude oil from an oil reserve, processing the stream of crudeoil in a dewatering unit to reduce an amount of process water in thestream of crude oil, monitoring aqueous breakthrough during theprocessing in real time, controlling the processing based on themonitored aqueous breakthrough, and distributing the processed stream ofcrude oil for transport to a refining facility.

The invention is also directed to a process for evaluating components ofa stream of crude oil in a refining operation, comprising providing astream of crude oil for processing, measuring particles in the stream ofcrude oil by determining the size of the particles, and identifying themeasured particles in the stream of crude oil.

Using the process, the stream of crude oil can be a desalted crude oilor a blend of at least two incompatible crude oils. Determining the sizeof the particles can include using focused beam reflectance.

The invention is also directed to a desalter for use in a refiningoperation, comprising a raw crude oil input, a wash water input in fluidcommunication with the raw crude oil input, including a mixer that mixesthe raw crude oil with the wash water, and a vessel in fluidcommunication with the raw crude oil input that receives the raw crudeoil and wash water mixture and a desalting mechanism connected to thevessel that operates on the mixture to dissolve salts from the mixture,to separate solids, and to separate the crude oil from the water. Thedesalter further comprises a desalted crude oil output in fluidcommunication with the vessel for discharging desalted crude oil forprocessing, a waste water output in fluid communication with the vesselfor discharging waste water, and at least one sensor connected to theoutput that measures particles and droplets in the desalted crude oiloutput and generates data based on the measurement. Other additives toenhance desalter performance such as coalescing and flocculation aidsmay also be added to either or both the water or crude oil during thedesalting process.

Preferably, the sensor is a particle measurement device including afocused beam reflectance device. An additional sensor can be connectedto the vessel that measures particles and droplets in the mixture in thevessel. A controller can be connected to the sensor for receiving thedata generated by the sensor and generating instructions based on thedata. The desalter can be in combination with a refining facility.

These and other aspects of the invention will become apparent when takenin conjunction with the detailed description and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in conjunction with the accompanyingdrawings in which:

FIG. 1 is a schematic drawing of desalter equipment in a processingfacility in accordance with this invention;

FIG. 2 is a schematic drawing of a dewatering unit in accordance withthis invention;

FIG. 3 is a graph showing the total particle counts detected by a sensorin accordance with this invention in crude oil following the addition ofseveral aliquots of fine iron oxide powder;

FIG. 4 is a graph showing the relation between total particle counts persecond and the amount of solid iron oxide added;

FIG. 5 is a graph showing the total particle counts detected by thesensor in accordance with this invention in crude oil following theaddition of several aliquots of brine; and

FIG. 6 is a graph showing the total particle counts detected by thesensor in accordance with this invention during the course of blendingtwo incompatible crude oils.

In the drawings, like reference numerals indicate corresponding parts inthe different figures.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

This invention is directed to a method of mitigating fouling, ingeneral. In a preferred use, the method and devices are applied to heatexchangers used in refining processes, such as in refineries orpetrochemical processing plants. The invention is particularly suitedfor use in the crude pre-heat train equipment, in combination with adesalter, but is also useful for other heat exchangers and otherprocessing equipment. Additionally, the invention can be used inpipestills (crude units), cokers, visbreakers, and the like. Of course,it is possible to apply the invention to other processing facilities andto other heat exchangers, particularly those that are susceptible tofouling in a similar manner as experienced during refining processes andare inconvenient to take off-line for repair and cleaning.

This invention is based on the recognition that it is desirable toeliminate or reduce fouling mechanisms in-process to prevent or minimizefouling. Moreover, the inventors recognize that it is desirable to takecorrective action when carry-over of aqueous brine and solids and/orprecipitation of solids happens before extensive downstream foulingoccurs. Such intervention can mitigate fouling and avoid the associatedcosts of cleaning fouled equipment.

In accordance with this invention, the process involves monitoring theoperation of a desalter in a processing facility. The operation of adesalter and the related processes are well known and are not discussedin detail except as it relates to the process invention describedherein.

FIG. 1 shows a basic schematic of a desalter 10. As is known, raw crudeoil is supplied to the process through a supply pipeline 12 andtypically arrives containing water, salts, and other solids. It is fedto a desalter to remove the soluble salts and some solids by beingpumped via a pump 14 to a desalting vessel 20. Upstream of vessel 20,the stream of raw crude oil is mixed with a stream of water 16 via amixing valve 18 and the mixture is delivered to the vessel 20. Otheradditives to enhance desalter performance, such as coalescing andflocculation aids, may also be added to either or both the water and/orcrude oil during the desalting process.

In the desalter vessel 20, typically an electric field is used toseparate the crude oil from the water containing the dissolved salts.Some insoluble solids, especially larger particles will settle andaccumulate at the bottom of the vessel 20 and are removed periodicallythrough ports on the bottom of the vessel (not illustrated). Likewise,fine particulate materials are often found at the interface of the oiland brine layers in vessel 20 and can be removed periodically as this“rag layer” accumulates. This can be accomplished by use of ports aswell, not illustrated in the figure. The desalted crude oil is outputvia a pipeline 22 to continue the processing. The water with thedissolved salts is drained from the vessel 20 via a drainage passage 24.

A known problem that occurs with desalting is that the desalted oil cancarry over aqueous brine, which contains dissolved salts such as sodiumchloride, and other solids. Carry-over can lead to fouling of downstreamheat exchange equipment, particularly the crude oil preheat exchangers,and can contribute to overhead corrosion of the pipestill.

As will be described below, a sensor 26 is provided to detect the outputfrom the vessel for carry-over of aqueous brine and solids. A sensor 28may also be provided to detect the solution in the vessel 20 to monitorthe desalting operation. Another sensor 29 could be used, if desired, tomonitor the quality of the incoming crude oil, such as contained in line12. The data collected from the sensors 26, 28, 29 is output to acontroller 30, for example, that can generate real-time information foran operator. It is also possible to use measuring equipment thatgenerates useful data without the assistance of a controller. However, acontroller can gather data from various sensors and process thecollected data and recommend correction action if desired. The operatoror an automatic controller can take corrective action if necessarybefore extensive downstream fouling occurs based on the sensed data byemploying various mechanisms, such as controlling the mixing valve, theflow rate of the water and crude oil, the flow rate of the output crudeoil and waste water, and other functions of the desalter 10, as would berecognized by those of ordinary skill in the art of petrochemicalprocessing.

Ideally, crude oil entering and exiting the desalter could be measuredand then the operation of the desalter could be optimized to maximizeremoval of brine, solids, and asphaltenes. Operating parameters, such ascrude inlet temperature, electrostatic grid voltage, crude/water mixingenergy, water addition rate, pH of water, and rate of additives toassist flocculation, could all be varied depending on the observedperformance.

The sensor or sensors 26, 28, 29 can be one or more measurementinstruments used to measure particles and droplets in the crude oilin-process and in real-time. Particles, in this context, can include anysecond immiscible phase found in the crude oil, such as salt brinedroplets, insoluble inorganic salts, solid corrosion byproducts, mineralmaterials, such as clays and aluminosilicates, and asphaltenes, forexample. The instrument should be suitable for measuring any solids ordispersed-phase concentrations in process and in real-time. One suitableinstrument that is commercially available is the Lasentec® Focused BeamReflectance Measuring (FBRM®) instrument made by Mettler Toledo.

The Lasentec® FBRM® collects total particle counts and cansimultaneously sort the total counts into “chord lengths” that relate tothe size of the particles counted. Thus, increases in certain sizes ofparticles can be distinguished. This assists in distinguishing betweenbrine breakthrough (represented as large droplets) and corrosionbyproducts (represented as fine particles). FBRM® is also available in avideo version that would enable an operator to visually see what isbeing counted as a “particle.” This would make it apparent when secondliquid phase droplets are being detected in contrast to solid particles.

In accordance with the process of this invention, the desalted crude oiloutput from the vessel 20 is detected using sensor 26 by collectingtotal particle counts and sorting the total counts into chord lengthsthat relate to the particles counted. By this, increases in certainsizes of particles can be distinguished. This allows particles to beidentified. For example, brine breakthrough can be evidenced by largedroplets, while corrosion by-products can be evidenced by fineparticles. If a video enhanced measuring instrument is used, theparticles being counted can be seen, which allows second liquid phaseparticles to be readily recognized. The data collected by the sensor isthen provided to an operator or controller to take corrective action asexplained above. This allows action to be taken when carry-over occursbut before fouling occurs.

The sensor 28 can also be used to monitor droplet size distribution ofwater added and mixed with the crude oil as part of the desaltingoperation. In this case, the mixture can be sampled and data can begathered regarding the aqueous phase. Then, the operation can beadjusted before the desalted oil is output. For example, if thedispersed aqueous phase is too fine, brine carry-over can occur becausethe droplets will take too long to coalesce in the desalter. When adispersion is too coarse or when insufficient mixing energy is provided,carry over of brine droplets can occur in which the brine droplets areencrusted with an organic and mineral coating that prevents theirdisruption and subsequent coalescence with the wash water. Fine tuningof the wash water and crude mixing can then be accomplished, which willenhance the desalter performance in general.

FIG. 2 is a schematic diagram of the invention in use in an upstreamoperation in petrochemical processing, such as a dehydration ordewatering system 40. In this case, a stream of crude oil 42 obtainedfrom an oil reserve by pumping is treated prior to shipping or transportvia a pipeline 44 in a dewatering or dehydration unit 44. The crude istreated in the dewatering unit 44 to reduce the amount of process waterin the crude. Aqueous breakthrough can be monitored in real time in thedewatering unit by a sensor 46, as described above, using focused beamreflectance measurement of particles. The unit 44 can then be optimizedvia a control mechanism 48. As this system is upstream and used at theinitial phase of processing, optimization of this process would providebenefits that would translate throughout the treatment process.

Another use for the process in accordance with this invention in which ameasuring instrument is used to detect particle size is to optimizecrude oil blending. Asphaltenes that separate as a second phase whenincompatible crude oils are blended can be detected to monitor theblending in real-time and avoid subsequent fouling due to theincompatibility. Closer approach to compatibility limits can be achievedif a method to detect the onset of asphaltene precipitation is used inreal-time monitoring.

This invention could also be used in other high fouling streams, such asin a fluidized bed catalytic cracking (FCC) cat slurry stream, which hasa high solids content. The measuring system of this invention wouldenable particle measurement and real-time feedback for systemoptimization.

The following experiments were conducted to show that the processdescribed above can detect brine and solids in crude oil.

Experiment 1

To demonstrate that fine solid particles at the 50 wppm concentrationlevel in crude oil can be detected, an experiment using the Lasentec®FBRM® was used. Two hundred mls of whole crude oil was poured into aglass beaker. This beaker was then positioned in the Lasentec® fixedbeaker stand that holds the Lasentec® probe in an optimal positionwithin the beaker in relation to a variable speed, four blade propellerstirrer that circulates the test solution past the probe window. Themeasurements were conducted at ambient temperature. After an initialtotal particle count was obtained with the instrument, data collectionwas halted. Then, about 10 mgs of iron oxide powder (Aldrich, <5 micron)was added to the crude oil in the beaker. The stirring rate wasincreased to 1000 rpm for 1 minute to fully disperse the solid, and thedata collection was resumed. A significant increase in the number ofparticle counts was observed. This procedure was repeated for two moreadditions of solids. The results are shown in FIG. 3. As seen in FIG. 3,the total count/sec at each increment of solids addition is representedby a plateau. FIG. 4 shows a plot of the correlation between totalcounts/sec measured by the Lasentec® FBRM® and the amount of solid addedto the crude. As can be appreciated from the graph, there is stronglinear correlation with an r²=0.998.

Experiment 2

A second experiment was conducted to demonstrate that brine dispersed incrude oil can be detected. The experiment used the Lasentec® FBRM® withthe same experimental set up and procedure as in the first experiment,described above, except that aliquots of a 20 weight % sodium chloridein water solution was added rather than the addition of aliquots ofsolid iron oxide. The first addition represented 0.1 volume %, and nochange in total particle counts was recorded. For the FBRM®, “particles”can be solid particles, gas bubbles, or dispersed second liquid phases,such as brine droplets, as in this case. Upon addition of 1 volume % ofbrine, a significant jump in signal was observed. Additional increasesof 2 volume % and 5 volume % also produced increases in particle counts,but not in a linear fashion, as in the first experiment. This may be dueto the unstable nature of the dispersion that is produced by theaddition of brine droplets, as brine droplets will coalesce with eachother over time and stick to glass beaker walls. It may be necessary toadd a dispersing agent to stabilize the aqueous dispersion and form astable emulsion to test the lower detection limits for brine in oilusing the FBRM®. The data obtained in the experiment is shown in thegraph of FIG. 5. This experiment suggests that at least 1 volume %carryover of brine in crude oil can be measured. The formation of stableemulsions in the desalter is one of the types of upsets that this methodcan readily detect.

Experiment 3

In a third experiment, the FBRM® probe was used to detect the formationof asphaltenes during the course of the blending of two incompatiblecrude oils. Initially, 250 mls of a crude oil was stirred at roomtemperature, and the probe was used to measure the background particlecontent. At room temperature, wax crystallites in the crude oil wereevident by eye and produced a noisy baseline to the FBRM®, as seen inFIG. 6. After an addition of 150 mls of n-heptane, most of the waxcrystals appeared to dissolve, and the total particle count dropped to asteady low level. Upon addition of 50 mls more of heptane, the particlecount increased dramatically. Initially, this growth was limited to thesmaller particles in the 0.8 and 5.5 micron chord length range. Then,the particles grew progressively larger. As indicated in FIG. 6, theLasentec® FBRM® was used to detect the “titration-like” response at thepoint of asphaltene phase separation. The absence and presence ofasphaltenes was confirmed by analysis of the test mixture under a lightmicroscope. High particle counts correlated with the presence ofasphaltenes under the microscope. This information is useful indetermining incompatibility numbers in a laboratory setting and may beused in crude oil blending in the refinery to monitor for the occurrenceof feed incompatibilities.

A follow up experiment was conducted in which asphaltene precipitationfrom one crude oil, Crude A, was induced by the addition of a second,incompatible crude oil, Crude B. The same titration-like response wasobtained.

Thus, it can be appreciated from the results of these experiments thatmeasuring particles and droplet size in crude oil can be effectivelyaccomplished. As demonstrated, aqueous brine and iron oxide solids canbe detected in crude oil by measuring particles using focused beamreflectance techniques. Using data generated from such measurements canbe used in accordance with this invention to mitigate fouling bycontrolling desalter operations and output in real-time to prevent orminimize carry-over of aqueous brine and particles. The data can also beused in accordance with this invention to control blending during themixing of incompatible crude oils to control the precipitation ofasphaltenes.

It will be recognized by those of ordinary skill in the heat exchangerart that the invention can be applied to any heat exchanger surface invarious types of known heat exchanger devices.

Various modifications can be made in the invention as described herein,and many different embodiments of the device and method can be madewhile remaining within the spirit and scope of the invention as definedin the claims without departing from such spirit and scope. It isintended that all matter contained in the accompanying specificationshall be interpreted as illustrative only and not in a limiting sense.

1. A process for optimizing a refining operation to mitigate fouling ofheat exchangers, comprising: processing raw crude oil in a desalter withwash water to remove particles from the crude oil; measuring particlesin the processed crude oil and generating data based on themeasurements; and adjusting the processing based on the data generatedfrom the measurements.
 2. The process of claim 1, wherein measuringparticles includes counting total particles.
 3. The process of claim 2,wherein measuring particles includes collecting the total particlecounts and sorting the counts based on particle size.
 4. The process ofclaim 3, wherein sorting the counts based on particle size includesdetermining a chord length for each particle counted.
 5. The process ofclaim 1, wherein measuring particles includes using focused beamreflectance.
 6. The process of claim 1, wherein generating data includesidentifying the particles.
 7. The process of claim 6, whereinidentifying the particles includes identifying the particles as one of aplurality of carry-over particles including salts, aqueous brine,asphaltenes, clays, alumino-silicates and corrosion by-products.
 8. Theprocess of claim 1, wherein measuring particles in the processed crudeoil occurs at the output of the desalter.
 9. The process of claim 1,wherein measuring particles in the processed crude oil occurs in thedesalter.
 10. The process of claim 1, further comprising whereinmeasuring particles in the unprocessed crude oil prior to processing inoccurs at the inlet of the desalter.
 11. The process of claim 1, whereinadjusting the processing includes controlling the wash water rate,mixing energy with the crude oil, pH and/or temperature.
 12. The processof claim 1, wherein adjusting the processing includes controlling atleast one of the wash water rate, mixing energy with the crude oil, pH,and temperature.
 13. The process of claim 1, wherein adjusting theprocessing includes controlling addition rates of chemical additives toenhance flocculation of solids and dispersancy of asphaltenes.
 14. Theprocess of claim 1, wherein adjusting the processing includescontrolling the applied voltage applied to the electrostatic grids inthe desalter.
 15. The process of claim 1, wherein measuring particlesand adjusting the process occurs in real-time.
 16. A process formonitoring aqueous breakthrough in a stream of crude oil, comprising:providing a stream of crude oil from an oil reserve; processing thestream of crude oil in a dewatering unit to reduce an amount of processwater in the stream of crude oil; monitoring aqueous breakthrough duringthe processing in real time; controlling the processing based on themonitored aqueous breakthrough; and distributing the processed stream ofcrude oil for transport to a refining facility.
 17. A process forevaluating components of a stream of crude oil in a refining operation,comprising: providing a stream of crude oil for processing; measuringparticles in the stream of crude oil by determining the size of theparticles; and identifying the measured particles in the stream of crudeoil.
 18. The process of claim 16, wherein the stream of crude oil isdesalted crude oil.
 19. The process of claim 16, wherein the stream ofcrude oil is a blend of at least two crude oils.
 20. The process ofclaim 16, wherein determining the size of the particles includes usingfocused beam reflectance.
 21. The process of claim 16, whereindetermining the size of the particles includes collecting total particlecounts and sorting the total counts based on chord lengths of eachmeasured particle.
 22. The process of claim 16, wherein providing thestream of crude oil for processing includes blending at least two crudeoils and identifying the particles includes identifying asphaltenes. 23.The process of claim 21, further comprising adjusting the processing byadjusting the blending based on compatibility.
 24. The process of claim16, wherein the stream is at least two crude oils that are incompatible.25. The process of claim 23, wherein particles are asphalteneprecipitates.
 26. The process of claim 16, wherein providing the streamof crude oil for processing includes providing a stream of raw crude oilto a desalter.
 27. The process of claim 25, wherein identifying theparticles includes identifying salts, aqueous brine droplets orcorrosion by-products.
 28. The process of claim 26, further comprisingadjusting the processing of the stream by adjusting a desalting processof the crude oil based on the identification of the measured particlesas aqueous brine carry-over.
 29. The process of claim 16, wherein thestream is FCC cat slurry.
 30. A desalter for use in a refiningoperation, comprising: a raw crude oil input; a wash water input influid communication with the raw crude oil input, including a mixer thatmixes the raw crude oil with the wash water; a vessel in fluidcommunication with the raw crude oil input that receives the raw crudeoil and wash water mixture and a desalting mechanism connected to thevessel that operates on the mixture to dissolve salts from the mixture,to separate solids, and to separate the crude oil from the water; adesalted crude oil output in fluid communication with the vessel fordischarging desalted crude oil for processing; a waste water output influid communication with the vessel for discharging waste water; and atleast one sensor connected to the output that measures particles anddroplets in the desalted crude oil output and generates data based onthe measurement.
 31. The desalter of claim 29, wherein the sensor is aparticle measurement device including a focused beam reflectance device.32. The desalter of claim 29, further comprising a sensor connected tothe vessel that measures particles and droplets in the mixture in thevessel.
 33. The desalter of claim 29, further comprising a sensorconnected to the vessel that measures particles and droplets in the rawcrude oil input mixture upstream of the vessel.
 34. The desalter ofclaim 29, further comprising a controller connected to the at least onesensor for receiving the data generated by the sensor and generatinginstructions based on the data.
 35. The desalter of claim 29, incombination with a refining facility.